Embodiments of the present invention disclose a method, an apparatus and a system for sending a physical layer signal, where the method for sending a physical layer signal includes: constructing a signal frame of a physical layer signal, where the signal frame includes one single-frequency sequence, the single-frequency sequence is used to enable a receiving apparatus to capture the signal frame in a frequency domain according to the single-frequency sequence, and the single-frequency sequence includes a plurality of single-frequency preset symbols; and sending the physical layer signal based on the signal frame. Applying the present invention can facilitate capturing the signal frame in a frequency domain by a receive end, and therefore, not only impact caused by frequency offset is overcome, but also multipath energy may be used effectively to improve performance of capturing.